Feline Lower Urinary Tract Disease, Calculi and Blocked Cats

Question 1

What is FLUTD?

Answer 1

A collection of conditions that can affect the bladder and/or urethra in cats

Question 2

What are some of the causes of FLUTD?

Answer 2

Question 3

What is a urethral plug?

Answer 3

• Protein-colloid matrix that’s made up of gunk basically…
  
  • mucoproteins
  • albumin
  • globulin
  • cells
    
    • red blood cells
    • white blood cells
    • epithelial cells
  • blood clots
• +/- crystalline material
  • Crystals might just get trapped in the plug
• Male cats can obstruct easily in this condition which is why its an emergency in practice

Question 4

Part of FLUTD clinical signs are some LUT signs - name some of these LUT signs

Answer 4

• Dysuria
• difficulty urinating
• vocalisation &/or pain
• Pollakiuria
• increased frequency
• Haematuria
• Stranguria
• straining to urinate
• similar/same as dysuria?
• Periuria
• urination in inappropriate places
• Signs of urethral obstruction?

Question 5

Part of FLUTD clinical signs are some behavioural changes - what do you see?

Answer 5

• Loss of house training
• Aggression
• Excessive grooming
• “Constipation”
• May be misinterpreted as this
• Stilted gait
• Abdominal pain
• Pain – likely part of the reason why these cats are so bad tempered usually

Question 6

What is the typical cat to get FLUTD?

Answer 6

• young or middle aged, but not older than 10 generally…
• Often overweight
• Relatively inactive
• mainly indoor
• eats dry food often
• multi cat house
• Not every cat with FLUTD ticks all of these boxes but these are most common

Question 7

What are some older theories that were used to propose the cause of iFLUTD?

Answer 7

Old theories included…

• Infectious agents
• bacteria
• virus
• mycoplasma
• Crystalluria
• Urachal diverticula
• Anatomical defect

Question 8

Why did people used to think that infectious agents were the cause of iFLUTD?

Answer 8

Why did people think this?

• Treatment with antibiotics seemed to work…
• Flare ups with stress could be viral…
• Crystalluria was often present…

Question 9

What is the significance of crystalluria with mucus plugs?

Answer 9

• Struvite crystals are common in healthy cats and in urethral plugs from obstructed cats and in non obstructed iFLUTD cats…
• No evidence that crystals damage uroepithelium
• Crystals may just get trapped in plugs of mucus

Question 10

What are the newer theories of the proposed causes of iFLUTD?

Answer 10

• Interstitial cystitis
• neurogenic inflammation
• mucosal defects
• Neuroendocrine imbalance
• This gets a bit quite challenging to discuss with owners as involved interaction between the way a cat perceives and responds to stress in their environment and what’s going on in the bladder lining – quite a difficult step to come to terms with

Question 11

What is neurogenic inflammation - is this a real syndrome?

Answer 11

Characterised by submucosal histopathological changes in the urothelium

• vasodilation
• vascular leakage
• absence of mononuclear or neutrophilic infiltrate
• increased mast cells (20% of patients)

So far there is a poor correlation between resolution of clinical signs and histopathology changes….there is much we don’t know!

Question 12

How can stress be a neuroendocrine trigger?

Answer 12

In normal cats stress causes activation of the hypothalamic pituitary adrenal axis with increased activity in the area of the brain dealing with vigilance and autonomic activity, increased catecholamine release, enhanced adrenal sensitivity to ACTH and increased secretion of glucocorticoids. In the normal situation one of the many glucocorticoid functions is to provide negative feedback and control the stress response. Cats with iFLUTD/ FIC and people suffering from some chronic pain syndromes essentially have an uncoupling of the hypothalamic-pituitary-adrenal axis –they are less able to cope with stress and have abnormal responses to stress.

Question 13

How can we compare cats and people with iFLUTD?

Answer 13

• People with IC (idiopathic cystitis) are at increased risk of IBS, depression, anxiety and hostility
• Owners of cats with FIC (feline idiopathic cystitis) observe fear, nervousness and aggression in their pets

Question 14

What is the brief pathophysiology of FLUTD?

Answer 14

Question 15

In a cat that has suspected FLUTD, what do we want to know about the clinical history?

Answer 15

• Is this the first episode or is it recurrent?
• feline idiopathic cystitis
• relapsing signs are common
• spontaneous recovery occurs in 4-7 days in most cases
• not all cases need treatment or investigations
• Are there any features that increase the likelihood of – we need to spot these
• UTI
• neoplasia
• Urolith
• If we are getting recurrent episodes, we may need to rule these things out

Question 16

On bladder palpation, what do we feel in a non-obstructed cat?

Systemic signs

Answer 16

• Bladder palpation
• small
• thickened?
• painful?
• Systemic signs are uncommon but could indicate concurrent disease

Question 17

On bladder palpation, what do we feel in an obstructed cat?

Systemic and other signs?

Answer 17

• Bladder palpation
• distended?
• Might still feel small but might be tense and painful. The sooner we catch obstructed cats, the better!
• Firm
• If not sure if it is or isn’t obstructed – safer to think you might need to pass a urethral catheter to check as a non-obstructed cat will have a very empty bladder and is tiny
• painful
• Penis discoloured +/or swollen
• Dehydrated
• Bradycardic – look for systemic signs!

Question 18

How quickly do clinical signs subside in cats with acute non-obstructive idiopathic cystitis WITHOUT treatment?

Answer 18

• Clinical signs subside within 5-7 days in up to 92% cats with acute non-obstructive idiopathic cystitis without treatment
• ie they get better irrespective of what we do!
• Recurrent episodes of acute iFLUTD tend to reduce in frequency and severity as a cat becomes older

Question 19

With a repeat offender of non-obstructed FLUTD, what should we rule out and what should we be doing as a means of investigation?

Answer 19

Rule out

• infection
• uroliths
• Neoplasia
• Maybe higher up the list in an older cat

What should we be doing?

1. haematology & biochemistry
2. urinalysis
3. radiography
4. ultrasound

Idiopathic disease becomes less likely if recurrent and severe episodes persist…. so at some point we have to think about ruling out other possible causes of LUT signs

A cat only has iFLUTD when we have ruled out all other causes. It’s often fine to assume a cat has iFLUTD to see if the signs resolve rather than putting the cat through all the investigations and the owner through all the expense of those investigations. BUT if things aren’t going smoothly ie the signs don’t resolve or get worse, the recurrent episodes are severe and frequent, the cat seems systemically ill- then we need to do more.

Question 20

How useful is haematoloy and biochemistry with FLUTD? What can we use it for?

Answer 20

• Limited role in non obstructed cats
• Search for concurrent disease?
• Are there any consequences you can detect?
• Underlying cause for uroliths?
• Concurrent disease is more likely in older cats…CKD, DM, HyperT4
• Is there something that would predispose to urolith formation…hypercalcaemia, PSS?
• Is there any consequence of the disease …..Fe deficiency anaemia with a chronic bleeding tumour?

Question 21

Crystalluria - fact or fiction?

What is the significance of crystalluria?

Answer 21

• crystals precipitate out in refrigerated samples
• crystalluria is a normal finding in cats
• crystals do not predict the urolith present
• crystals have no role in urethral obstruction but might get trapped in the mucus plug
• Thinking about the significance of crystalluria varies but generally avoid over interpreting this finding- it is unhelpful in most cases!

Question 22

Why might radiography might be more valuable than US for FLUTD?

Answer 22

Think about why radiography might be more valuable than ultrasound

• US skillful technique, radiographs you can take well and ask for a second opinion
• Somethings might be more difficult to identify on an US exam

Question 23

What can we use survery radiography for with FLUTD/calculi/blocked cat?

Answer 23

• Identification of radio opaque uroliths – plain radiographs can be useful and potentially we are less likely to miss stones on plain radiograph than we might be on an US scan – can be easy to miss things
• Typical fat cat…might be hard to palpate the bladder- don’t assume it’s OK if the signs could be associated with urethral obstruction.

Question 24

What can we use contrast radiography for with FLUTD/calculi/blocked cat?

Answer 24

Identification of

• bladder wall thickness & integrity
• radiolucent calculi
• tumours, polyps or diverticulae
• urethral abnormalities
• stricture
• urolithiasis
• rupture

Question 25

Why might we image the urethra?

Answer 25

Rule out radiolucent urolith +/or stricture in relapsing cases

Question 26

What is the best way to highlight calculi?

Answer 26

Double contrast cystography is best way to highlight calculi (which can be missed with other techniques) and is the most helpful technique to assess bladder wall

If male tom with repeated obstruction, can sometimes get traumatic stricture develop at sight where there has been some iatrogenic damage from a previous catheterisation attempt

Question 27

What is the problem with abdominal US with FLUTD/calculi/blocked cats?

Answer 27

• Highly dependent on equipment and expertise ….
• Differentiation a mass from a hematoma is not always as easy as it should be!
• Its never wrong to repeat an US study if you aren’t sure what’s going on
• Doppler studies are not easy but can help differentiate a bladder mass (vascularised) from a haematoma

Question 28

Artefact or calculus?

Answer 28

Comparing a colon distorting the bladder with a calculus in the bladder

Colon on left indenting into the bladder

Calculus on right – can be easily missed if not that experienced!

Be ware of artefacts

Question 29

What are some systemic signs of a urethral obstruction?

Answer 29

Systemic signs of urethral obstruction:

• Anorexia
• Vomiting
• Depression
• Circulatory shock
• These could occur with all things in a cat – but if firm, unhappy bladder then make sure you think of it as a possible urethral obstruction case!

Question 30

How can the male urethra be a cause of urethral obstruction?

Answer 30

The male urethra has fundamental design flaws

Can see how narrow this part of their anatomy is

Can be tricky doing retrograde studies

Urethra is small and goes through quite a significant bend! Good place to lodge mucus plugs and can be difficult to catheterise

Question 31

With urethral calculi are radio opaque?

Answer 31

• struvite
• calcium oxalate

Question 32

What are some causes of urethral obstruction in IFLUTD?

Answer 32

Functional (not physical) obstruction

• urethral spasm
• mucosal oedema
• Cats often have functional obstruction rather than physical obstruction – these are easier to catheterise if we go about in the right way

INFLAMMATION

Question 33

What are some systemic signs in OBSTRUCTED FLUTD?

Answer 33

•Managing urethral obstruction is an emergency because systemic problems develop including hyperkalaemia and AKI. As you already know (! see AKI lecture) successful management of AKI means we have to correct the underlying cause while the renal injury is still reversible.

ECG patter changes

Question 34

How can/should we stabilise the patient and sedate or GA it when unblocking a male cat?

Answer 34

• Stabilise the patient
• what does this mean?
• Sedation or GA?
• Analgesia! Want urethra to relax
• Appropriate depth of anaesthesia and analgesia will sometimes relieve urethral spasm and allow catheterisation very easily.
• GA might be preferable as will get better analgesia
• Cystocentesis?
• relieve the back pressure

Question 35

Explain how to unblock a male cat after you have stabilised and sedated/GA the patient

Answer 35

• Extrude the penis & massage gently
• To see if you can massage out any plug material as sometimes right at the tip of the penis – anything too vigorous will make it worse! Try to milk out urethral plug that may be contributing to the obstruction
• Appropriate catheter
• open ended so we can flush effectively, not out the side holes, but through the end hole
• small
• well lubricated
• Straighten the urethra
• pull the penis dorsal and caudally
• If you just pull down, making the bend in the urethra worse – then you try to catheter and it just jabs around, can get more risk of urethral rupture
• Saline flushing as catheter advanced
• Rectal palpation
• relieves urethral spasm
• helps retrograde hydropulsion
• Flush with saline – hopefully opening up the urethra a bit so that you can float the catheter in and it isn’t scratching so much

Question 36

Is cystocentesis ok to do in a blocked cat?

Answer 36

• better option than bladder rupture and worsening AKI
• empty the bladder as much as you can
• Cystocentesis in urethral obstruction cases is controversial ie some clinicians think it carries an increased risk of urine leakage in to the peritoneal cavity. In my opinion (and I am not alone!) a small needle puncture in a bladder which is otherwise healthy will not cause a problem especially if we empty the bladder as much as possible through that one needle hole. Relief of back pressure makes it easier to flush the urethra and push any obstruction (plug/calculus) back in to the bladder AND the kidneys are grateful because they can start to produce urine again.

Question 37

How can we manage hyperkalaemia in blocked cats?

Answer 37

• Think about an ECG monitor
• what would you expect to see?
• Manage oliguria/anuria
• fluid therapy to restore renal perfusion and GFR (if dehydrated/hypovolaemic)
• relieve any urethral obstruction
• ie allow the kidneys to excrete K+
• Protect the heart
• calcium gluconate slow iv
• Increase K+ uptake by cells
• glucose 1-2mls/kg (50% soln) diluted and given iv
• might encourage release of endogenous insulin
• +/- soluble insulin CRI?
• Managing urethral obstruction is an emergency because systemic problems develop including hyperkalaemia and AKI. As you already know (! see AKI lecture) successful management of AKI means we have to correct the underlying cause while the renal injury is still reversible.
• Calcium- antagonises the effects of hyperkalaemia (cardioprotective) but only for about 20-30 minutes

Question 38

How should we manage indwelling catheters?

Antibiotics?

Answer 38

• Don’t leave it in for any longer than you need to
• Use a closed urine collection system
• Don’t give antibiotics with an indwelling catheter
• Wait and give them if you need to when you remove the catheter!
• Catheters can be irritant if left in unnecessarily and provide a great means of access for opportunist bacteria
• INDWELLING CATHETERS NEED TO BE SOFT

Question 39

What is the bad news about iFLUTD?

Answer 39

• Recurrence of clinical signs has been reported to affect between 39-65% cats with acute iFLUTD within 1-2 years of the initial event
• A small group of cats develop chronic persistent signs for weeks or months
• investigations are justified to be sure nothing else is going on and that your diagnosis of iFLUTD is correct
• Signs can recur frequently in some cats
• investigations justified as above

Question 40

What is the emergency treatment for FLUTD?

Answer 40

• Stabilise the patient
• Identify obstruction or bladder rupture
• Manage obstruction or rupture
• iFLUTD…
• pain relief – is important, but not always easy to achieve in these cats – relieving the pain associated with the procedures if easy but resolving underlying pain in the bladder is a problem
• how do we treat a disease if we don’t understand the cause?
• Minimise stress
• How do we do this?
• Keep cat in with urethral catheter in hospital environment – this is not great on the stress management!

Question 41

How can we control the discomfort in a cat with FLUTD with medication?

Answer 41

• Buprenorphine
• no contraindications
• Glucocorticoids
• no benefit in clinical trials
• ? contraindicated
• NSAIDs
• placebo controlled trial with meloxicam showed no benefit (Dorsch 2009 ECVIM)
• It’s hugely frustrating that we view iFLUTD as an inflammatory disease (neurogenic inflammation) but this does not seem to respond to standard anti inflammatory treatment.

Question 42

How can we control the discomfort in a cat with FLUTD with flushing?

Answer 42

Flush the bladder with

• saline –> urohydrodistension –> some benefit?
• lidocaine
• people: provided relief of clinical signs beyond the initial treatment phase after 5 consecutive days of treatment
• cats: no proven benefit in a small number of cats treated for 3 consecutive days

Question 43

As part of the long term management & prevention of FLUTD, how can we increase water intake?

Answer 43

AIM: produce a dilute urine in the long term to reduce recurrence rate with these cats

• wet diet
• frequent smaller meals?
• free access to water
• water fountains
• dripping taps
• broths/flavoured ice cubes
• tuna water?
• bolied meat?

Need to work with the cat and do what it likes and do what encourages them to drink…

Question 44

What are some problem areas to consider wioth sociology and FIC?

Answer 44

Problem areas to consider:

• Multi cat households
• Inter-cat conflict
• Number of social groups? Conflict can be just as important between social groups compared to just individual cats
• Stress plays an important role in triggering idiopathic cystitis in cats and a number of studies have highlighted that multi a households with inter cat conflict are problematic. It seems likely that it is the number of social groups rather than the number of individual cats that is the real DYNAMITE factor

Question 45

Can stress reduction pheromones help with FLUTD?

Answer 45

• no significant difference Feliway vs. placebo BUT favourable trends
• 5/9 owners thought cats were better
• 4/9 saw no difference
• Its always worth a try! Feliway diffusers etc.

Question 46

How can we used environmental enrichment to deal with FLUTD as part of long term treatment and prevention?

Answer 46

Environmental modification has been shown to be associated with

• decreased LUT signs
• normalisation of
• circulating catecholamines
• bladder permeability
• cardiac function
• reduced response to acoustic startle
• If certain nervous pathways within the bladder can be stimulated by the brain in response to stress, are we able to reduce the likelihood of this happening for example by environmental enrichment?

Question 47

How can glycosaminoglycans be used potentially for the treatment of FLUTD?

Are they useful?

Answer 47

Protect the bladder lining? The gag layer that lines mucosa is probably a really important defence mechanism in the bladder, can provide gag precursors but seems far fetched sometimes

• N-acetyl glucosamine
• GAG precursor
• available in the UK
• BUT placebo controlled trial…no significant overall benefit
• But probably wont do any harm! Don’t expect to be the be all and end all

Question 48

How can anxiolytics and muscle relaxants be used potentially for the treatment of FLUTD?

Are they useful?

Answer 48

• Anxiolytics?
• amitriptyline
• tricyclic antidepressant, anticholinergic, antihistaminic, anti inflammatory, analgesic…
• helpful for IC in women
• controversial in cats and has side effects
• Seems to have some evidence to suggests its helpful in people as anti-inflammatory for neurogenic inflammation patterns? But also likely sedates the cats and makes them more subdued and less bothered by their bladders – controversial.
• Muscle relaxants
• dantrolene
• Prazosin
• For cats that have urethral spasm – but again, controlled clinical trials haven’t shown much evidence to suggest beneficial
• No proven benefits other than anecdotal and small studies. Focus more on behavioural aspects.
• Sometimes less is more…